Preheat the oven to 350 degrees. Coat a 9x13-inch baking pan with cooking spray.

In a large bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt. Set aside.

Using a handheld mixer or stand mixer fitted with the paddle attachment, beat the butter on high speed until smooth and creamy. Add both sugars and beat on high until well blended, about 1 to 2 minutes, scraping down the sides of the bowl as necessary.

Beat in the eggs, one at a time. Beat in the mashed bananas and vanilla.

With the mixer on low speed, beat in half of the flour mixture until just blended. Beat in the buttermilk. Beat in the remaining flour mixture until just blended. Don't over-mix, even if there are a few small lumps.

Pour the batter into the prepared pan and top with the chocolate chips.

Bake for 30 to 40 minutes, until a wooden pick inserted near the center comes out clean or with little moist bits clinging to it.

Cool the cake on a wire rack for 5 minutes before slicing and serving.

Store leftovers in an airtight container.